The present invention relates to an injection molding apparatus comprising two injection molding units and, more particularly, to an injection molding apparatus comprising an exchanger for automatically exchanging a chuck mechanism of a work pickup device arranged on its top portion.
Conventionally, an injection molding apparatus which comprises two injection molding units and operates these units independently to efficiently mold works is known, and is commercially available. In particular, in order to control and optimally operate two injection molding units, an automatic operation control system is known, as described in, e.g., Japanese Patent Publication No. 61-9128. When such an automatic operation control system is adopted, the two injection molding units can optimally and efficiently injection-mold works, and production efficiency can be improved.
However, even if the operations of the two injection molding units are optimally controlled, the two injection molding units are independently installed in a conventional factory layout, and each unit has an exclusive mold exchanging mechanism. For this reason, a problem of inefficient use of an installation space of a factory is pointed out.
The number of types of works which can be molded by a single injection molding apparatus is very large since metal molds can be exchanged. Thus, many chuck mechanisms for picking up works are necessary in correspondence in number with the types of metal molds in accordance with the shapes of the works. When metal molds are exchanged, a work pickup device of the chuck mechanism must be exchanged. However, the chuck mechanism is manually exchanged in the present state, thus posing a problem of low work efficiency.